Phone thinks it's charging with no cable plugged in

Well...., did this one to my self. Gnex got fairly wet in the bottom of a snowtube :frown:. Dried it off quickly as soon as I was aware, and tried the "put the phone in a bag a rice" trick
for a few days afterwards.

Everything works except, the phone charging indicator stays on even after the phone is fully charged and I've removed the USB cable. When the battery reaches 14% capacity,
the audio/visual warning repeats 3-5 times within lets say a 10second span (which REALLY kills the battery). Lastly, when plugging a USB cable from my Mac to the phone,
it takes several tries for the Mac to see it.

I've already tried a new battery in the GNex, but the behavior is the same. Anyone gone through something similar? Any way to repair this?

This sounds like a hardware problem that plagues quite a few people. The first and easiest thing to do is to check the USB port. Look for lint or whatever else that may have made it into there and try and clean it if you can. Also, look for things that are out of wack, apparently the tongue-like thing (not really sure of what the technical term for it is) inside there can get bent a bit out of place and cause this as well. These tend to be temporary fixes if anything though. Generally they stop working, and people have to have their device serviced or replaced to remedy this.

If that fails, it will likely need some repairs. Unfortunately since you got it wet, the warranty is probably void if it hadn't expired previously. Also, since it got wet, there are some other things that could have gone wrong, which will make diagnosing the problem a bit harder.

Depending on your know-how, I have heard of many people fixing this by themselves. This requires you to at least partially dismantle the phone, then put it back together. Repairing Samsung Galaxy Nexus (Verizon LTE) Micro USB Charge Port & Main Mic - iFixit <-- there may be better guides than that, probably some videos too but just showing a general guide. The actual piece that you are replacing probably will cost you ~ $10 (make sure you get the right one for your specific Nexus if you go this route). You could also get it repaired by someone, Samsung does this.

Once again this is assuming the water didn't damage other things, and that this is your problem. But there are quite a few people that are hit by this issue, many haven't had water damage.